I can confirm that if you stop drinking water, in 72 hours or so you won't have to worry about microplastics.

This.

Avoiding plastic in your day to day might prevent leeching, which is nice, but you'll still encounter it in the natural environment.

The problem is the plastics never really chemically break down. They do undergo mechanical weathering though, so it all breaks down into smaller and smaller pieces over time. Eventually these particles are microscopic, and make their way into everywhere and everything it seems, from soil to rainwater to your breakfast cereal and your testicles.

You can probably filter it out of your water, I imagine reverse osmosis is likely effective since plastic molecules are somewhat chonky. A HEPA filter should get at least the larger particles out of the air. I don't know how effective it'd be with smaller particles, sometimes called nanoplastics. Avoiding synthetic fabrics probably would help somewhat, but I haven't read anything about this.

You can't get it out of your food though, we don't know enough yet about reliable ways we could keep plants from taking it up through their root systems. From plants it gets into the food chain, and much like mercury with fish, it'll likely end up concentrating in animals, like us. You could potentially grow your own food via aquaponics using filtered water and maybe keep it plastic-free, but this is a real reach here. And you're basically vegan now and have to literally grow all your own food.

Note, I'm largely speculating regarding methods.

Some reading material, this first one is about plant uptake:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8618759/

Water filtration:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10054062/